September weather in Castlewood, SD
The average temperature in Castlewood in September is 59.9°F (47.3°F–72.4°F). Average precipitation: 2.69 inches.
September is a fall month in Castlewood, and is warmer than the annual average of 42.7°F. Daily temperatures swing about 25.1°F between overnight low and afternoon high. Daylight averages about 12h 18m. For travel, September is a comfortable month to visit.
Avg High
72.4°F
Avg Low
47.3°F
Precipitation
2.69 in
Daylight
12h 18m
September records in Castlewood
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 91.9°F (2013) | 48.0°F (2020) | 0.17 in (2014) |
| September 2 | 93.0°F (2012) | 44.1°F (2013) | 0.75 in (2018) |
| September 3 | 93.0°F (2023) | 42.1°F (2022) | 2.03 in (2021) |
| September 4 | 98.1°F (2023) | 35.1°F (2025) | 0.18 in (2023) |
| September 5 | 97.0°F (2023) | 36.0°F (2025) | 0.73 in (2016) |
| September 6 | 90.0°F (2013) | 35.1°F (2025) | 0.56 in (2016) |
| September 7 | 90.0°F (2013) | 30.9°F (2025) | 0.10 in (2016) |
| September 8 | 89.1°F (2013) | 35.1°F (2012) | 0.90 in (2019) |
| September 9 | 93.0°F (2022) | 34.0°F (2020) | 0.95 in (2016) |
| September 10 | 82.0°F (2013) | 30.0°F (2020) | 0.40 in (2019) |
| September 11 | 88.0°F (2012) | 28.9°F (2020) | 0.34 in (2019) |
| September 12 | 91.9°F (2012) | 37.9°F (2022) | 1.42 in (2019) |
| September 13 | 87.1°F (2017) | 34.0°F (2014) | 0.10 in (2019) |
| September 14 | 88.0°F (2017) | 36.0°F (2016) | 0.74 in (2021) |
| September 15 | 89.1°F (2015) | 39.0°F (2012) | 0.25 in (2023) |
| September 16 | 87.1°F (2012) | 36.0°F (2014) | 0.54 in (2022) |
| September 17 | 89.1°F (2018) | 35.1°F (2023) | 0.81 in (2021) |
| September 18 | 86.0°F (2019) | 28.0°F (2012) | 1.51 in (2025) |
| September 19 | 91.0°F (2013) | 30.9°F (2012) | 0.50 in (2013) |
| September 20 | 88.0°F (2023) | 46.0°F (2012) | 0.96 in (2018) |
| September 21 | 84.9°F (2022) | 35.1°F (2013) | 0.59 in (2019) |
| September 22 | 87.1°F (2015) | 27.0°F (2012) | 0.03 in (2022) |
| September 23 | 88.0°F (2017) | 21.0°F (2012) | 0.85 in (2017) |
| September 24 | 82.9°F (2020) | 25.0°F (2012) | 2.40 in (2017) |
| September 25 | 79.0°F (2012) | 35.1°F (2021) | 0.31 in (2015) |
| September 26 | 84.0°F (2014) | 28.9°F (2012) | 0.32 in (2017) |
| September 27 | 87.1°F (2021) | 27.0°F (2012) | 0.02 in (2017) |
| September 28 | 84.0°F (2012) | 28.9°F (2022) | 1.50 in (2013) |
| September 29 | 90.0°F (2024) | 28.9°F (2022) | 0.20 in (2023) |
| September 30 | 90.0°F (2025) | 36.0°F (2012) | 0.21 in (2021) |